An mp refining unit treats medium sweet charge oil with N-methyl-2-pyrrolidone solvent, hereafter referred to as mp, in a refining extractor to yield raffinate and extract mix. The mp is recovered from the raffinate and from the extract mix and returned to the extractor. A system controlling the refining unit includes a gravity analyzer, a refractometer and viscosity analyzer, all analyzing the medium sweet charge oil and providing corresponding signals, sensors sense the flow rates of the charge oil and the mp flowing into the refining tower and the temperature of the extract mix and provide corresponding signals. One of the flow rates of the medium sweet charge oil and the mp flow rates is controlled in accordance with the signals from all the analyzers and all the sensors, while the other flow rate of the medium sweet charge oil and the mp flow rates is constant.
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1. A control system for an mp refining unit receiving medium sweet charge oil and N-methyl-2-pyrrolidone, one of which is maintained at a fixed flow rate while the flow rate of the other is controlled by the control system, wherein said refining unit treats the received charge oil with the received methyl-2-pyrrolidone to yield extract mix and raffinate, comprising gravity analyzer means for sampling the medium sweet charge oil and providing a signal api corresponding to the api gravity of the medium sweet charge oil, refractometer means for sampling the medium sweet charge oil and providing a signal RI corresponding to the refractive index of the charge oil, viscosity analyzer means for sampling the medium sweet charge oil and providing signals KV150 and KV210 corresponding to the kinematic viscosities, corrected to 150° F. and 210° F., respectively, sulfur analyzer means for sampling the medium sweet charge oil and providing a signal S corresponding to the sulfur content of the medium sweet charge oil, flow rate sensing means for sensing the flow rates of the medium sweet charge oil and of the N-methyl-2-pyrrolidone and providing signals CHG and SOLV, corresponding to the medium sweet charge oil flow rate and the N-methyl-2-pyrrolidone flow rate, respectively, means for sensing the temperature of the extract mix and providing a corresponding signal t, and control means connected to all of the analyzer means, to the refractometer means, and to all the sensing means for controlling the other flow rate of the charge oil and the N-methyl-2-pyrrolidone flow rates in accordance with signals api, KV210 , KV150, S, RI, CHG, t and SOLV.
2. A system as described in
3. A system as described in
where C5 through C12 are constants; and SUS210 network means connected to the SUS signal means and to the ΔVI signal means and receiving direct current voltages C13 through C16 for providing signal SUS210 to the ΔVI signal means in accordance with signal SUS, voltages C13 through C16 and the following equation: SUS210 =[C13 +C14 (C15 -C16)]SUS, where C13 through C16 are constants. 4. A system as described in
K150 =C2 -[1n(t150 +C3)]/C4, where C2 through C4 are constants, and t150 corresponds to a temperature of 150° F.; H150 signal means connected to the viscosity analyzer means and receiving a direct current voltage C1 for providing a signal H150 corresponding to a viscosity H value for 150° F. in accordance with signal KV150 and voltage C1 in the following equation: H150 =1n1n(KV150 +C1), where C1 is a constant; H210 signal means connected to the viscosity analyzer means and receiving voltage C1 for providing signal H210 corresponding to a viscosity H value for 210° F. in accordance with signal KV210, voltage C1 and the following equation: H210 =1n 1n(KV210 +C1), H100 signal means connected to the K signal means, to the H150 signal means and the H210 signal means for providing a signal H100 corresponding to a viscosity H value for 100° F., in accordance with signals H150, H210 and K150 and the following equation: H100 =H210 +(H150 -H210)/K150 KV100 signal means connected to the H100 signal means and receiving voltage C1 for providing a signal KV100 corresponding to a kinematic viscosity for the charge oil corrected to 100° F. in accordance with signal H100, voltage C1, and the following equation: KV100 =exp[exp(H100)]-C1, and VI memory means connected to the KV100 signal means and to the viscosity analyzer means having a plurality of signals stored therein, corresponding to different viscosity indexes and controlled by signals KV100 and KV210 to select a stored signal and providing the selected stored signal as signal VI. 5. A system as described in
where C17 through C22 are constants, a VIDWCP signal means connected to the VIDWCO signal means and to the SUS210 signal means for providing VIDWCP signal, corresponding to the viscosity index of the dewaxed charge oil at a predetermined temperature, in accordance with signals SUS210 and VIDWCO, voltages C20 through C25 and Pour, and the following equation:
where POUR is the pour point of the dewaxed product and C23 through C25 are constants, and subtracting means connected to the J signal means and to the VIDWCP signal means and receiving voltage VIRP for subtracting signal VIDWCP from voltage VIRP to provide the VI signal to the J signal means. 6. A control system as described in
where C26 through C35 are constants. 7. A control system as described in
where C36 through C45 are constants. 8. A system as described in
C =(SOLV)(100)/J, so as to cause the apparatus means to change the charge oil flow to the new flow rate. 9. A system as described in
SO =(CHG)(J)/100, so as to cause the N-methyl-2-pyrrolidone flow to change to the new flow rate. |
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1. Field of the Invention
The present invention relates to control systems and methods in general and, more particularly, to control systems and methods for oil refining units.
A lube oil refining unit treats medium sweet charge oil with N-methyl-2-pyrrolidone solvent, hereafter referred to as MP, in a refining extractor to yield raffinate and extract mix. The MP is recovered from the raffinate and from the extract mix and returned to the extractor.
A system controlling the refining unit includes a gravity analyzer, a sulfur analyzer, a refractometer and viscosity anlayzers. The anlayzers analyze the medium sweet charge oil and provide corresponding signals. Sensors sense the flow rates of the charge oil and the MP flowing into the extractor and the temperature of the extract-mix and provide corresponding signals. The flow rate of the medium sweet charge oil or the MP is controlled in accordance with the signals provided by all the sensors and the analyzers while the other flow rate of the medium sweet charge oil or the MP is constant.
The objects and advantages of the invention will appear more fully hereinafter from a consideration of the detailed description which follows, taken together with the accompanying drawings wherein one embodiment of the invention is illustrated by way of example. It is to be expressly understood, however, that the drawings are for illustration purposes only and are not to be construed as defining the limits of the invention.
FIG. 1 shows a lube oil refining unit in partial schematic form and a control system, constructed in accordance with the present invention, in simple block diagram form.
FIG. 2 is a detailed block diagram of the control means shown in FIG. 1.
FIGS. 3 through 13 are detailed block diagrams of the H computer, the K signal means, the H signal means, the KV computer, the VI signal means, the SUS computer, the SUS210 computer, the VIDWCO computer, the VIDWCP computer, the ΔRI computer and the J computer, respectively, shown in FIG. 2.
cl DESCRIPTION OF THE INVENTION
An extractor 1 in a lube oil refining unit is receiving medium sweet charge oil by way of a line 4 and a methyl-2-pyrrolidone solvent, hereafter referred to as MP, by way of a line 7 and providing raffinate to recovery by way of a line 10, and an extract mix to recovery by way of a line 14.
Medium sweet charge oil is a charge oil having a sulfur content equal to or less than a predetermined sulfur content and having a kinematic viscosity, corrected to a predetermined temperature, less than a first predetermned kinematic viscosity but equal to or less than a second predetermined kinematic viscosity. Preferably, the predetermined sulfur content is 1.0%, the predetermined temperature is 210° F., and the first and second predetermined kinematic viscosities are 7.0 and 15.0, respectively. The temperature in extractor 1 is controlled by cooling water passing through a line 16. A gravity analyzer 20, viscosity analyzers 23 and 24, a refractometer 26 and a sulfur analyzer 28 sample the charge oil in line 4 and provide signals API, KV210, KV150, RI and S, respectively, corresponding to the API gravity, the kinematic viscosities at 210° F. and 150° F., the refractive index and sulfur content, respectively.
A flow transmitter 30 in line 4 provides a signal CHG corresponding to the flow rate of the charge oil in line 4. Another flow transmitter 33 in line 7 provides a signal SOLV corresponding to the MP flow rate. A temperature sensor 38, sensing the temperature of the extract mix leaving extractor 1, provides a signal T corresponding to the sensed temperature. All signals hereinbefore mentioned are provided to control means 40.
Control means 40 provides signal C to a flow recorder controller 43. Recorder controller 43 receives signals CHG and C and provides a signal to a valve 48 to control the flow rate of the charge oil in line 4 in accordance with signals CHG and C so that the charge oil assumes a desired flow rate. Signal T is also provided to temperature controller 50. Temperature controller 50 provides a signal to a valve 51 to control the amount of cooling water entering extractor 1 and hence the temperature of the extract-mix in accordance with the set point position and signal T.
The following equations are used in practicing the present invention for medium sweet charge oil:
H210 =1n1n(KV210 +C1) (1)
where H210 is a viscosity H value for 210° F., KV210 is the kinematic viscosity of the charge oil at 210° F. and C1 is a constant having a preferred value of 0.6.
H150 =1n1n(KV150 +C1) (2)
where H150 is a viscosity H value for 150° F., and KV150 is the kinematic viscosity of the charge oil at 150° F.
K150 =[C2 -1n(T150 +C3 ]/C4 (3)
where K150 is a constant needed for estimation of the kinematic viscosity at 100° F., T150 is 150 , and C2 through C4 are constants having preferred values of 6.5073, 460 and 0.17937, respectively.
H100 =H210 +(H150 -H210)/K150 (4)
where H100 is a viscosity H value for 100° F.
KV100 =exp[exp(H100)]-C1 (5)
where KV100 is the kinematic viscosity of the charge oil at 100° F.
| ______________________________________ |
| SUS = C5 (KV210 ) + [C6 + C7 (KV210)]/[C8 + |
| C9 (KV210) 6. |
| + C10 (KV210)2 + C11 (KV210)3 |
| ](C12) |
| ______________________________________ |
where SUS is the viscosity in Saybolt Universal Seconds and C5 through C12 are constants having preferred values of 4.6324, 1.0, 0.03264, 3930.2, 262.7, 23.97, 1.646 and 10-5, respectively.
SUS210 =[C13 +C14 (C15 -C16)]SUS (7)
where SUS210 is the viscosity in Saybolt Universal Seconds at 210° F. and C13 through C16 are constants having preferred values of 1∅ 0.000061, 210 and 100, respectively.
| ______________________________________ |
| VIDWC0 = |
| C17 - C18 (VI) + C19 (S)2 - C20 |
| (RI)(API) 8. |
| + C21 (API)(VI) - C22 (API) (S) |
| ______________________________________ |
where VIDWCO is the viscosity index of the charge oil for 0° F. and C17 through C22 are constants having preferred values of 838.96, 11.504, 3.1748, 19.19, 0.42412 and 0.38322, respectively.
| ______________________________________ |
| VIDWCP = |
| VIDWCO + (Pour) [C23 - C24 lnSUS210 |
| 9. |
| + C25 (lnSUS210)2 ] |
| ______________________________________ |
where VIDWCP and Pour are the viscosity index of the dewaxed product at a predetermined temperature and the Pour Point of the dewaxed product, respectively, and C23 through C25 are constants having preferred values of 2.856, 1.18 and 0.126, respectively.
ΔVI =VIRO -VDWCO =VIRP -VIDWCP, (10)
where VIRO and VIRP are the VI of the refined oil at 0° F., and the predetermined temperature, respectively.
| ______________________________________ |
| ΔRI = |
| [C26 - C27 (ΔVI) - C28 (KV210)2 + |
| C29 (VI)2 11. |
| - C30 (KV210)(API) + C31 (ΔVI)(KV210) |
| + C32 (API)(S) - C33 (VI)(S) - C34 (ΔVI)2 |
| ]C35, |
| ______________________________________ |
where ΔRI is the change in the refractive index from the charge oil to the raffinate, VI is the viscosity index of the medium sweet charge oil and C26 through C35 are constants having preferred values of 386.48, 14.544, 1.4528, 0.01232, 1.4923, 2.4913, 27.217, 8.3297, 0.056978 and 10-4, respectively.
| ______________________________________ |
| J = C36 + C37 (ΔRI) - C38 (T) + C39 (T)2 |
| + C40 (S)(T) 12. |
| + C41 (KV210)(T) - C42 (VI) - C43 (S) - C44 |
| (ΔRI)(T) |
| + C45 (ΔRI)(ΔVI), |
| ______________________________________ |
where J is the MP dosage and C36 through C45 are constants having preferred values of 271.97, 83944, 4.648, 0.026549, 11.487, 0.32774, 4.6927, 3103.3, 610.25 and 759.81, respectively.
C = (SOLV)(100)/J (13)
where C is the new charge oil flow rate.
Referring now to FIG. 2, signal KV210 is provided to an H computer 50 in control means 40, while signal KV150 is applied to an H computer 50A. It should be noted that elements having a number and a letter suffix are similar in construction and operation as to those elements having the same numeric designation without a suffix. All elements in FIG. 2, except elements whose operation is obvious, will be disclosed in detail hereinafter. Computers 50 and 50A provide signals E1 and E2 corresponding to H210 and H150, respectively, in equations 1 and 2, respectively, to H signal means 53. K signal means 55 provides a signal E3 corresponding to the term K150 in equation 3 to H signal means 53. H signal means 53 provides a signal E4 corresponding to the term H100 in equation 4 to a KV computer 60 which provides a signal E5 corresponding the term KV100 in accordance with signal E4 and equation 5 as hereinafter explained.
Signals E5 and KV210 are applied to VI signal means 63 which provides a signal E6 corresponding to the viscosity index.
AN SUS computer 65 receives signal KV210 and provides a signal E7 corresponding to the term SUS in accordance with the received signals and equation 6 as hereinafter explained.
An SUS 210 computer 68 receives signal E7 and applies signal E8 corresponding to the term SUS210 in accordance with the received signal and equation 7 as hereinafter explained.
A VIDWCO computer 70 receives signals RI, S, API and E6 and provides a signal E10 corresponding to the term VIDWCO in accordance with the received signals and equation 8 as hereinafter explained.
A VIDWCP computer 72 receives signal E8 and E10 and provides a signal E11 corresponding to the term VIDWCP in accordance with the received signals and equation 9. Subtracting means 76 performs the function of equation 10by subtracting signal E11 from a direct current voltage V9 corresponding to the term VIRP, in equation 10, to provide a signal E12 corresponding to the term ΔVI in equation 10.
A ΔRI computer 79 receives signals E6, E12, KV210, S and API and provides a signal ΔRI, corresponding to the term ΔRI in equation 11, in accordance with received signals and equation 11 as hereinafter explained.
A J computer 80 receives signals T, KV210, ΔRI, S, E6 and E12 and provides a signal E13 corresponding to the term J in accordance with the received signals and equation 12 as hereinafter explained to a divider 83.
Signal SOLV is provided to a multiplier 82 where it is multiplied by a direct current voltage V2 corresponding to the term (SOLV)(100) in equation 13. The produce signal is applied to divider 83 where it is divided by signal E13 to provide signal C corresponding to the desired new charge oil flow rate.
It would be obvious to one skilled in the art that if the charge oil flow rate was maintained constant and the MP flow rate varied, equation 13 would be rewritten as
SO=(J) (CHG)/100 (14)
where SO is the new solvent flow rate. Control means 40 would be modified accordingly.
Referring now to FIG. 3, H computer 50 includes summing means 112 receiving signal KV210 and summing it with a direct current voltage C1 to provide a signal corresponding to the term [KV210 +C1 ]shown in equation 1. The signal from summing means 112 is applied to a natural logarithm function generator 113 which provides a signal corresponding to the natural log of the sum signal which is then applied to another natural log function generator 113A which in turn provides signal E1.
Referring now to FIG. 4, K signal means 55 includes summing means 114 summing direct current voltage T150 and C3 to provide a signal corresponding to the term [T150 +C3 ]which is provided to a natural log function generator 113B which in turn provides a signal corresponding to the natural log of the sum signal from summing means 114. Substracting means 115 subtracts the signal provided by function generator 113B from a direct current voltage C2 to provide a signal corresponding to the numerator of equation 3. A divider 16 divides the signal from subtracting means 115 with a direct current voltage C4 to provide signal E3.
Referring now to FIG. 5, H signal means 53 includes subtracting means 117 which subtracts signal E1 from signal E2 to provide a signal, corresponding to the term H150 -H210, in equation 4, to divider 118. Divider 118 divides the signal from subtracting means 117 by signal E3. Divider 118 provides a signal which is summed with signal E1 by summing means 119 to provide signal E4 corresponding to H100.
Referring now to FIG. 6, a direct current voltage V3 is applied to a logarithmic amplifier 120 in KV computer 60. Direct current voltage V3 corresponds to the mathematical constant e. The output from amplifier 120 is applied to a multiplier 122 where it is multiplied with signal E4. The product signal from multiplier 122 is is applied to an antilog circuit 125 which provides a signal corresponding to the term exp (H100) in equation 5. The signal from circuit 125 is multiplied with the output from logarithmic amplifier 120 by a multiplier 127 which provides a signal to antilog circuit 125A. Circuit 125A provides a signal to subtracting means 128 which subtracts a direct current voltage C1 from the signal from circuit 125A to provide signal E5.
Referring now to FIG. 7, VI signal means 63 is essentially memory means which is addressed by signals E5, corresponding to KV100, and signal KV210. In this regard, a comparator 130 and comparator 130A represent a plurality of comparators which receive signal E5 and compare signal E5 to reference voltages, represented by votlages R1 and R2, so as to decode signal E5. Similarly, comparators 130B and 130C represent a plurality of comparators receiving signal KV210 which compare signal KV210 with reference voltages RA and RB so as to decode signal KV210. The outputs from comparators 130 and 130B are applied tn an AND gate 133 whose output controls a switch 135. Thus, should comparators 130 and 130B provide a high output, AND gate 133 is enabled and causes switch 135 to be rendered conductive to pass a direct current voltage VA corresponding to a predetermined value, as signal E6 which corresponds to VI. Similarly, the outputs of comparators 130 and 130C control and AND gate 133 A which in turn controls a switch 135A to pass or to block a direct current voltage VB. Similarly, another AND gate 133B is controlled by the outputs from comparators 130A and 133B is controlled by the outputs from comparators 130A and 130B to control a switch 135B so as to pass or block a direct current voltage VC. Again, an AND gate 133C is controlled by the outputs from comparators 130A and 130C to control a switch 135C to pass or to block a direct current voltage VD. The outputs of switches 135 through 135C are tied together so as to provide a common output.
Referring now to FIG. 8, the SUS computer 65 includes multipliers 136, 137 and 138 multiplying signal KV210 with direct current voltages C9, C7 and C5, respectively, to provide signals corresponding to the terms C9 (KV210), C7 (KV210) and C5 (KV210), respectively in equation 6. A multiplier 139 effectively squares signal KV210 to provide a signal to multipliers 140 41. Multiplier 140 multiplies the signal from multiplier 39 with a direct current voltage C10 to provide a signal corresponding to the term C10 (KV210)2 in equation 6. Multiplier 141 multiplies the signal from multiplier 139 with signal KV210 to provide a signal corresponding to (KV210)3. A multiplier 142 multiplies the signal from multiplier 141 with a direct current voltage C11 to provide a signal corresponding to the term C11 (KV210)3 in equation 6. Summing mean 143 sums the signals from multipliers 136, 140 and 142 with a direct current voltage C8 to provide a signal to a multiplier 144 where it is multiplied with a direct current voltage C12. The signal from multiplier 137 is summed with a direct current voltage C6 by summing means 145 to provide a signal corresponding to the term [C6 +C7 (KV210)]. A divider 146 divide the signal provided by summing means 145 with the signal provided by multiplier 144 to provide a signal which is summed with the signal from multiplier 138 by summing means 147 to provide signal E7.
Referring now to FIG. 9, SUS210 computer 68 includes subtracting means 148 which subtracts a direct current voltage. C16 from another direct current voltage C15 to provide a signal corresponding to the term (C15 -C16) in equation 7. The signal from subtracting means 148 is multiplied with a direct current voltage C14 by a multiplier 149 to provide a product signal which is summed with another direct current voltage C13 by summing means 150. Summing means 150 provides a signal corresponding to the term [C3 +C14 (C15 -C16 ]in equation 7. The signal from summing means 150 is multiplied with signal E7 by a multiplier 152 to provide signal E8.
Referring now to FIG. 10, VIDWCO computer 70 includes a multiplier 155 multiplying signal E6 with a direct current voltage C18 to provide a signal corresponding to the term C18 (VI) in equation 8. A multiplier 160 multiplies signal E6 and API to provide a signal to another multiplier 163 where it is multiplied with a direct current voltage C21. Multiplier 163 provides a signal corresponding to the term C21 (API)(VI) in equation 8. A multiplier 167 multiplies signals API and RI to provide a signal which is multiplied with a direct current voltage C20 by a multiplier 170 which provides a signal corresponding to the term C20 (RI)(API). Signals S and API are multiplied by a multiplier 174 to provide a signal to yet another multiplier 176 where it is multiplied with a direct current voltage C22. Multiplier 176 provides a signal corresponding to the term C22 (API)(S). A multiplier 180 effectively squares signal S and provides a signal to another multiplier 184 where it is multiplied with direct current voltage C19. Multiplier 184 provides a signal corresponding to the term C19 (S)2.
Summing means 188 effectively sums the positive term in equation 8 by summing the signals from multipliers 163 and 184 with a direct current voltage C17 to provide a sum signal. Summing means 190 effectively sums the negative terms in equation 8 when it sums the signals from multipliers 155, 170 and 176 to provide a sum signal. Subtracting means 195 subtracts the sum signal provided by suming means 190 from the sum signal provided by summing means 188 to provide signal E10.
VIDWCP computer 72 shown in FIG. 11, includes a natural logarithm function generator 200 receiving signal E8 and providing a signal corresponding to the term 1nSUS210 to multipliers 201 and 202. Multiplier 201 multiplies the signal from function generator 200 with a direct current voltage C24 to provide a signal corresponding to the term C24 1n SUS210 in equation 10. Multiplier 202 effectively squares the signal from function generator 200 to provide a signal that is multiplied with the direct current voltage C25 by a multiplier 205. Multiplier 205 provides a signal corresponding to the term C25 (1n SUS210)2 in equation 9. Subtracting means 206 subtracts the signals provided by multiplier 201 from the signal provided by multiplier 205. Summing means 207 sums the signal from subtracting means 206 with a direct current voltage C23. A multiplier 208 multiplies the sum signals from summing means 207 with a direct current voltage POUR to provide a signal which is summed with signal E10 by summing means 210 which provides signal E11 .
Referring now to FIG. 12, ΔRI computer 79 includes multipliers 220, 225 and 227 which effectively square signals E6, E12 and KV210. Multipliers 230 and 231 multiply signal KV210 with signals E12 and API, respectively. Multipliers 235, 236 multiply signal S with signals API and E6, respectively, to provide product signals while a multiplier 238 multiplies signal E12 with a direct current voltage C27 to provide a signal corresponding to the term C27 (ΔVI). Multipliers 221, 240, 241, 243, 244 and 245 multiply the product signals from multipliers 220, 225, 230, 227, 231, 235 and 236, respectively, with direct current voltages C29, C34, C31, C28, C30, C32 anc C33, respectively, to provide signals corresponding to the term C29 (VI)2, C34 (ΔVI)2, C31 (ΔVI), C28 (KV210)2, C30 (KV210)(API), C32 (API)(S) and C33 (VI)(S), respectively.
Summing means 250 effectively sums the positive terms of equation 11 by summing signals from multipliers 221, 241 and 244 with a direct current voltage C26 to provide a sum signal. Summing means 253 effectively sums the negative terms of equation 11 when it sums the signals from multipliers 238, 240, 242, 243 and 245 to provide a sum signal. Subtracting means 255 subtracts the signal provided by summing means 253 from the signal provided by summing means 250 to provide a signal to a divider 257. Divider 257 divides the signal with a direct current voltage C35 to provide signal ΔRI.
Referring now to FIG. 13, J computer 80 includes multipliers 270, 271, 272 and 273 multiplying signals E6, T, S and ΔRI, respectively, with direct current voltages C42, C38, C43 and C37, respectively, corresponding to the terms C42 (VI), C38 (T), C43 (S) and C37 (ΔRI), respectively, in equation 12. Multiplier 278 effectively squares signal T and provides a product signal to another multiplier 280 where it is multiplied with a direct current voltage C39 to provide a signal corresponding to the term C39 (T)2. Multiplier 284 multiplies signals T and KV210 to provide a signal to a multiplier 285 where it is multiplied with a direct current voltage C41. Multiplier 285 provides a signal corresponding to the term C41 (KV210)(T) in equation 12. Signals S and T are multiplied by a multiplier 288 to provide a signal to yet another multiplier 290 where it is multiplied with a direct current voltage C40. Multiplier 290 provides a signal corresponding to the term C40 (S)(T). Signals T and ΔRI are multiplied by a multiplier 295 which provides a signal to a multiplier 297 where it is multiplied with a direct current voltage C44 to provide a signal corresponding to the term C44 (ΔRI (T). A multiplier 300 multiplies signals E12 and ΔRI to provide a signal to a multiplier 303 where it is multiplied with a direct current voltage C 45 to provide a signal corresponding to the term C45 (ΔRI)(ΔVI).
Summing means 305 effectively sums the positive terms of equation 11 when it sums a direct current voltage C36 with the signals from multipliers 280, 285, 290, 273 and 303 to provide a sum signal. Summing means 306 effectively sums the negative terms of equation 11 when it sums the signals from mutlipliers 270, 271, 272 and 297 to provide a sum signal. Subtracting means 310 subtracts the sum signal provided by summing means 306 from the sum signal provided by summing means 305 to provide signal E13 corresponding the MP dosage.
The present invention as hereinbefore described controls an MP refining unit receiving medium sweet charge oil to achieve a desired charge oil flow rate for a constant MP flow rate. It is also within the scope of the present invention, as hereinbefore described, to control the MP flow rate while the medium sweet charge oil flow is maintained at a constant rate.
Barger, Frank L., Sequeira, Jr., Avilino
| Patent | Priority | Assignee | Title |
| 4349884, | Dec 15 1980 | Texaco Inc. | Feedstock temperature control system |
| 4354242, | Dec 15 1980 | Texaco Inc. | Feedstock temperature control system |
| Patent | Priority | Assignee | Title |
| 4161427, | Nov 16 1977 | Bechtel Corporation | Control system for a furfural refining unit receiving medium sweet charge oil |
| 4162197, | Nov 16 1977 | Bechtel Corporation | Furfural refining unit control system |
| 4164450, | Nov 16 1977 | Bechtel Corporation | Control system for a furfural refining unit receiving light sour charge oil |
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| Oct 19 1978 | Texaco Inc. | (assignment on the face of the patent) | / | |||
| Apr 19 1996 | Texaco Inc | Bechtel Corporation | ASSIGNMENT OF ASSIGNORS INTEREST SEE DOCUMENT FOR DETAILS | 008022 | /0422 |
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